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exploratory testing

How can lessons from Luigi’s Mansion apply to software testing and automation?

Luigi’s Mansion is a popular Nintendo video game series. It’s basically Ghostbusters in the Super Mario universe: Luigi must use a special vacuum cleaner to rid haunted mansions of the ghosts within. Along the way, Luigi also solves puzzles, collects money, and even rescues a few friends. I played the original Luigi’s Mansion game for the Nintendo GameCube when I was a teenager, and I recently beat the sequel, Luigi’s Mansion: Dark Moon, for the Nintendo 3DS. They were both quite fun! And there are some lessons we can apply from Luigi’s Mansion to software testing and automation.

#1: Exploratory Testing is Good

The mansions are huge – Luigi must explore every nook and cranny (often in the dark) to spook ghosts out of their hiding places. There are also secrets and treasure hiding in plain sight everywhere. Players can easily miss ghosts and gold alike if they don’t take their time to explore the mansions thoroughly. The same is true with testing: engineers can easily miss bugs if they overlook details. Exploratory testing lets engineers freely explore the product under test to uncover quality issues that wouldn’t turn up through rote test procedures.

#2: Expect the Unexpected

Ghosts can pop out from anywhere to scare Luigi. They also can create quite a mess of the mansion – blocking rooms, stealing items, and even locking people into paintings! Software testing is full of unexpected problems, too. Bugs happen. Environments go down. Network connections break. Even test automation code can have bugs. Engineers must be prepared for any emergency regardless of origin. Software development and testing is about solving problems, not about blame-games.

#3: Don’t Give Up!

Getting stuck somewhere in the mansion can be frustrating. Some puzzles are small, while others may span multiple rooms. Sometimes, a player may need to backtrack through every room and vacuum every square inch to uncover a new hint. Determination nevertheless pays off when puzzles get solved. Software engineers must likewise never give up. Failures can be incredibly complex to identify, reproduce, and resolve. Test automation can become its own nightmare, too. However, there is always a solution for those tenacious (or even hardheaded) enough to find it.

Want to see what software testing lessons can be learned from other games? Check out Gotta Catch ’em All! for Pokémon!

Behavior-driven development takes an automation-first philosophy: behavior specs should become automated tests. However, BDD can also accommodate manual testing. Manual testing has a place and a purpose, even in BDD. Remember, behavior scenarios are first and foremost behavior specifications, and they provide value beyond testing and automation. Any behavior scenario could be run as a manual test. The main questions, then, are (1) when is manual testing appropriate and (2) how should it be handled.

When is Manual Testing Appropriate?

Automation is not a silver bullet – it doesn’t satisfy all testing needs. Scenarios should be written for all behaviors, but they likely shouldn’t be automated under the following circumstances:

The return-on-investment to automate the scenarios is too low.

The scenarios won’t be included in regression or continuous integration.

The behaviors are temporary (ex: hotfixes).

The automation itself would be too complex or too fragile.

The nature of the feature is non-functional (ex: performance, UX, etc.).

The team is still learning BDD and is not yet ready to automate all scenarios.

Manual testing is also appropriate for exploratory testing, in which engineers rely upon experience rather than explicit test procedures to “explore” the product under test for bugs and quality concerns. It complements automation because both testing styles serve different purposes. However, behavior scenarios themselves are incompatible with exploratory testing. The point of exploring is for engineers to go “unscripted” – without formal test plans – to find problems only a user would catch. Rather than writing scenarios, the appropriate way to approach behavior-driven exploratory testing is more holistic: testers should assume the role of a user and exercise the product under test as a collection of interacting behaviors. If exploring uncovers any glaring behavior gaps, then new behavior scenarios should be added to the catalog.

How Should Manual Testing Be Handled?

Manual testing fits into BDD in much the same way as automated testing because both formats share the same process for behavior specification. Where the two ways diverge is in how the tests are run. There are a few special considerations to make when writing scenarios that won’t be automated.

Repository

Both manual and automated behavior scenarios should be stored in the same repository. The natural way to organize behaviors is by feature, regardless of how the tests will be run. All scenarios should also be managed by some form of version control.

Furthermore, all scenarios should be co-located for document-generation tools like Pickles. Doc tools make it easy to expose behavior specs and steps to everyone. They make it easier for the Three Amigos to collaborate. Non-technical people are not likely to dig into programming projects.

Tags

Scenarios must be classified as manual or automated. When BDD frameworks run tests, they need a way to exclude tests that are not automated. Otherwise, test reports would be full of errors! In Gherkin, scenarios should be classified using tags. For example, scenarios could be tagged as either “@manual” or “@automated”. A third tag, “@automatable”, could be used to distinguish scenarios that are not yet automated but are targeted for automation.

Extra Comments

The conciseness of behavior scenarios is problematic for manual testing because steps don’t provide all the information a tester may need. For example, test data may not be written explicitly in the spec. The best way to add extra information to a scenario is to add comments. Gherkin allows any number of lines for comments and description. Comments provide extra information to the reader but are ignored by the automation.

It may be tempting to simply write new Gherkin steps to handle the extra information for manual testing. However, this is not a good approach. Principles of good Gherkin should be used for all scenarios, regardless of whether or not the scenarios will be automated. High-quality specification should be maintained for consistency, for documentation tools, and for potential future automation.

An Example

Below is a feature that shows how to write behavior scenarios for manual tests:

Feature: Google Searching
@automatedScenario: Search from the search bar
Given a web browser is at the Google home page
When the user enters "panda" into the search bar
Then links related to "panda" are shown on the results page
@manualScenario: Image search
# The Google home page URL is: http://www.google.com/ # Make sure the images shown include pandas eating bambooGiven Google search results for "panda" are shown
When the user clicks on the "Images" link at the top of the results page
Then images related to "panda" are shown on the results page

It’s not really different from any other behavior scenarios.

As stated in the beginning, BDD should be automation-first. Don’t use the content of this article to justify avoiding automation. Rather, use the techniques outlined here for manual testing only as needed.